Electric zinc-furnace with integral condenser.



BEST AVAILABLE COP.

J. THOMSON. ELECTRIC ZINC PURNACE WITH INTEGRAL CONDENSER..

APPLICATION FILED JAN. 2, 1913. y

1,080,862.v` l l Patented Dec.9,1913.

2SHBBTSSHEET 1. Q C u tu G 1 S LL Nii a l D`r/rl/k/ F163.

BEST AvAxLAeLE COP.

J. THOMSON. ELECTRIC ZINC FURNAGE WITH INTEGRAL GONDENSER.

` APPLICATION FILED JAN. 2, 191s.

- 080,862. n Paten 1390.9, 1913.

2 HEETS-SHEET 2.

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EEST'AVAILABLE coe.

JOHN THOMSON, OE NEW YORK, N. Y. f

ELECTRTC ZINC-summon WTTH INTEGRAL CONDENSEE.` f A appii'aiijgii inea January 2,1913. Y ser-iai No. 739,788.

T a all whom it may concern:

Re it known that-l, JOHN THOMSON, a citizen of the United States, and a. resident of the borough of Manhattan of the city of New York, vin the county and State ot' Yew York, have invented certain new and useful Improvements in Electric Zinc-Furnaces with .Integral Condensers, of which the following is a-speciication, reference being made to thc accompanying drawings, forming a part hereof.

This invention relates to the metallurgy of zinc and an object thereof is to produce metallic zinc fun'ies b v the reduction of o xid of zinc (Zu()) by carbon (C) and to subsequently condense saidzinc fume to liquid metal.' The lient necessary for decomposing the ZnO and C' is preferably derived from an electric current vpassed through a resistor. i

The invention especially resides in particular means designed to accomplish the Objects above stated.

The resistor above mentioned is coinprised in a bed 'of carbon usually niade of coke, which is disposed upon air open refractorr grating'and'is confined by side walls;-- lThe size fand shape of the carbon pieces as -nell as the depth, width and length of the resistor bedlnay be variously modiliedf-toi obtain any-desired electrical resistance Vand inteiisity;,-Of.- current, which is brought to the -:twof,ends' the resistor by blocksoframorphous carbon or graphite sitvuated in'tlie'end walls of the reaction chain'T ber, that. is, the resistor is interpolated be.- tween the two terminals.

llie reaction chamber ofthe furnace is made of sutiicient. deptl to receive the charge -wliichis placedz directly upon and is sustained bye-the. resistor. 'llie cliai'gc;in1ts entirety 1s either a mixture or alternate-'layersof oxid of zinc and of carboninrpreferably substantially the relative proportions to effect when suitably heated practically the complete reduction tric" energy. .is.transformed into caloric en- 5- ergy in tliefre'sistor hed ofthe iurnaee and 'l speciacation of Letters Patent.

1an-einen of, i 91s.

" "Qcfin the heat thus generated, iftlie-.teiiiperatre is adequate, ell'ects the decomposition of the superimposed mass, the following chemical reaction ensuing:

ZnO-l-CzZn-l-CO.

In the constructions illustrated thewalls of the iirnace immediately adjacent tO the longitudinal sides of the resistor 'and its superimposed charge are more or less utilized 'to 'condense the zinc fume, to collect-` the liquid metal and t'o evacuate the residual, gases. ln other words, the longitudinal walls of the reaction chamber are somewhat utilized for the purpose of condensini.-

The manner of connecting the carbon ter-q minals to the bus-bars or main line. cables are matters of importance and A,thesinparts have been improved in their Ydetails, OEE con-' struction.

The fundamental principle-sA applicable' to the condensation of zinc u ine, arewell uns derstood and need not behere, repeated at..

length. lVhen the ZnO-l- C'iteaction is`em-v ployed the resulting classical formula is n'ot precisely7 realized in a .commercial i furnace oieration that is at the rimar A 7 7 instant of the reaction. for thcre are always present sensible quantities'of airandvater which may be both intimately entrained'and in chemical combination Withth materials also be present to a deleterious'riitent and this-is especially true if the ca rbon is in the forni of ordinary colte. Sonieo' the e'ets of oxidizing elements such as air and water maybe to precipitate an objectionable portion of the .fume .in tluxforni ot. blue pow- 'comprising the charge. SulfifflS) ,ni.1 V

the accompanyingY drawings'iorniing a part.

of this specification, andv in which'- l*`igure 1 is a trans-reise 'center section, the

lower or lett hand 'portion of the' igiire de noting one manner of realizing the invention` while the upper 'or right hand portionA of the figure denotes'another manner of real# lling the invention, the section being along BEST Avait/isis ooey i gitudinal center section as on the line A of Fig. l, and illustrates at the opposite rightand left hand portions different forms for realizing the invention; Fig. 8 is a detached, broken plan view of the carbon terminals, showing the attachment ot the electrodes, and Fig. 4 is a diagram denoting modifications in the wall construction.

The restricted dimensions of l?atent Otlice sheets do not permit a scale reduction fromv working drawings, hence the several figures are to be regarded as merely illustrative embodiments ot' the invention, indicative of the principles employed.

R is the reaction chamber, S the inner side walls of said chamber, T, T1L the outer side Walls, V the resistor, H the charge, D the carbon terminals, J the hearth, N, N1 the zinc reservoirs, and W the residue sump.

The grate which forms the hearth is built from spaced refractory bars or plates 5 which rest'on ledges 6 formed in the tam ed sole 7, and beneath the'grate is the resi( ue sump or chamber W. 'The rate bar spaces 8 are to be such that the pieces of resistor .carbon will bridge them, but in any case they will serve to permit the inert ash or sintery residue, either by gravitation or. by pokingrom above, to pass through and collect below. This also permits if desired that dissolvent material such as lime may be fed in at intervals and the temperature of the' resistor be temporarily considerably increased above the normal, whereby a viscous or semi-liquid or even a liquid slag will be produced. Ii the slag is liquefied it may be tapped olf, but means for doing this are not shown. In this wise the resistor may be run for a longer period of time when if the inert residue is collected upon a solid hearth. In

fact the operation may continue until the ultimate accumulation of .residue in the sump-willvbe such thatit becomes advisable to remove it and this will only occur at con? siderable intervals, days, weeks 'or even longer. Now, to effect this removal the resistor and thefree grate bars may be taken out, the snmpis emptied 'as by means of tongs, forks or shovels, and a new resistor is laid, vall-df which may be done quickly.

- The carbon terminals D are built into the end walls X of the i,urnace. They preferably lie horizontally to the resistor with which their inner ends make contact. These.

rods are preferably beveled backfrom the vertical, as 9, Fig. 2, whereby'the weight of the overlying material tends to maintain intimacy of contact between them and the carbon bed. In prior practice the terminals have been carried entirely through and beyond the outer faces of the-furnace walls with'the disadvantage of loss, in heat radi ation,- ;requiring a considerably greater length of carbon, interfering with the application of wallbracing and increasing the electrical of. energy to all portions of the terminals.

Vhile the inner clamping portions of these electrodes may become quite hot, the loss in conductivity thus caused is easily compensated by providing an excess of section in the metal. On the other hand, such heat as may be conducted outwardly will, because of the large surface of the tang-ends 10, be readily dissipated to atmosphere.

The reaction chamber is virtually an open shaft in which the charge' is maintained and usually without a cover. But it has been found advantageous not to load the resistor with an excessively dee supply of reacting materials. When the shaft is open the top of the charge may be said to serve as a portion of the upper surface of the furnace. By frequently applying thin layers of react-A ing materials, say at a rate to compensate the decomposition and slightly tamping the upper surface, air is adequately excluded and the heat loss by radiation is minimized. On the other hand, as a certain amount of pressure is developed in and above the reaction zone, there is opportunity for vapor, steam. or dioXid of carbon to ,percolate upwardly away from the resistor, to mingle with the atmosphere, and the freedom of escape may .be readily augmented at intervals by forcing Zone where the temperature is highest and directlyV and immediately from the sides of 1 the resistor into perforations, ducts, slots, slits or spaces formed in the longitudinal side walls of the furnace.

ature progressively with each and every incrementof distance away from the active' v The boundary .surfaces of said Spaces diminish in tempern reaction zone and also-from the sides of the resistor, but the temperature of the said spaces at their inlets will be nearly if not fully equal to that of the entering fume and as. In the operationV of this furnace and its integral condenser the temperature Y at or near to the'impingement of the charge upon the resistor, the same as in the rei sistor itself, should be maintained suiiso \ charge-'f 'tdi-Which they are adjacent..

BEST/ivm cieutly high to prevent the existence of CO2. lt is-*manitcst, however` that the lower the temperature in the resistor the better will be the results from certain points of view.

'lwo" diffcrentforins of condensing sys- `temsare show-n in Figs. 1 and 2, and for'- simplieity of dcsript-ien euch will be. to la: certain extent separately referred to. Thus,'= (sec the upper 'or-right hand halt of Fig. porlimtotth'efiuneirside walls may he: 'lorinedotscseral-sn'perimposed series of refractory;round;'rods l2, the. lower series heingtii'stf laid, and st imevvhat separated lonv'wally'.` Then upon'. this lower series 1 pp'errodsA are .l'l'aclced. thereby forming Lf-'gered'structure-ivith a large number oi" -iiiterrening spaces 1?. The rods are preferably laid so as to slope downwardly 'from the reaction chamber. as shown, and if desired theymayalso be canted sideu'ise instead of lying at.- approximately a transverserightfa-nglel' These rods may also be arrangedi so- 1.1 o foccupy posi tions other tha'rfthosc just: described. l`lie innerzcnds of thiscliiodsi 1in faittqnovide a portion; of

' ellis-,dime into intimate physii'f'illttlie A'sides' of the. resistor portion-of the charge as may he deemed to be subjected 'to a sufli'ciently high reactiontempc'rature, As a consequence'ofthis construction and arrangement the inner ends or' the rods will acquire and he maintained at or 'about'ithe'ffsame temperature as that of 'tlie'i-e`.-`sisl'o1"- and that portion of the The temperature of 'the duct surfaces formed by the rods will progressively fall in passing from thereducing-zene and with a rapidity ivhich will/be afunction ofthe material employed 'Wh'ichimay be such as fire 'clay or 're-crystallizedcarborundurm carbon or the like. 1- 1- The aim of the construction is toproduce in the Walls a large number of lateral spaces, slits, ducts-or`perforations, each of restricted tlovvfarea bu't'f'of considerable aggregate area and heatditlusing surface..- The round rods meet 4this condition satisfactorily for the reason that; aside from their nearly neg; ligible line contacts, they do when staggered closely substantially present a minimum of flow area along their lineal spaces with a maximumv of circumferential surface. It is feasible, however, to practically realize the above mentioned conditions b'y. a builtup or mol-dedf-structure wherein thence-1s alarge nuinber offfssures, -perforations orf slits' such, as`l4gslzoivn' m the lente' "-0. #left-1 hand halfof Fig. 2.

Particular reference is'now ldirected t0 ing witlrthe product-s receivedfrom the in-- v y ner walls. Thesin the lower orleft 'hand furnace.

'constructed with a largenunlber of outer series of Wall slots is into a vertical chamber or gallery 15. Any coalesced or liquelied zinc will-fall on to the sloped conduit 16 and 'float-"into the zinc receptacle N which is; disposed along the outside wall of the The outer wall T is preferably down-sloping ducts, slots or-slits 17 whose :inner openings connect with the aforesaid gallery and whose outer opemngs lead to the atmosphere. lVhatever is received in the gallery in the form of a gas or fumes is permitted or forced to escape from said gallery 'through these outer .and consequently colder orifices. The result of this, arrangement. is that a second opportunity is aiorded for extraction of heat from the fume and thus aid in the formation of liquid metal, in which case the latter will fall down along the surface 18 of the wall into the underlying zinc receptacle while any residual g'as may mingle with the a'ir or be burned to CU2.

In the upper or right hand portion of Fig. 1- the construction andfunction of the inner Wall S is substantially the same as has already been described; but the vertical gal-v lcry is divided as by means of a suspended plate 1!) into two sections, an inner20, and an, outer 1 8.. The zinc receptacle N is here constructed Within the contines of thefurnace and 'immediately beneath the lower open ends of the aforesaid galleries. The outer right hand wall Tl is formed in about the same manner as that of the left hand' wall, except that the slope of its ducts or; slits 22 is downwardly and inwardly, that is, toward the sectional gallery. Now7 'as indicated by the arrows, all'of the products of the'reaction evacuated into the innergalf lery section :'20 is forced to flow downwardly and into the zinc receptacle space and any remaining volatile matter must low upsvardlyp into the outer gallery section 18, from whence it enters the wall spaces 22, and such liquid zinc as is produced in these spaces Will tloiv back int-o the gallery and than another, i'vhich in fact is likely to occur, the flow of the ongoing volatile products will to a material extent be compensated or equalized.

When the inyentionis practisedas shoiyng by the rglitilianddialfgf I"i'g.j1,' the residi'lal 'gaseous matte" which Lleaves .the outer.. eng .of the slots Q,enters l.a chamber'Ql-irhich blanket all cgitliefdiischarge ends of the perl Eromthis chamber Q, the :rt-lf mosphere ma., reached through side ports... vor a port, as23,noj1;ro m its uppexendporf" tion, as 24. This chamber-is' utilizable for for-ations sEsT AVAILABLE coe.

the collection of blue powder or oxidized residuals which may be intermittently withdrawn from the bottom 'of said chamber through openings or an opening such as 25.

5 Moreover, the top of this chamber may be provided with cups or a recess, as O, having perforated or slitted bottoms as the'plate 26.

Pieces of broken carbon, as 27, can be placed in said cups to perform the function of a final strainer or filter at the tail end of the condensing circuit.

Now, reverting to the main members of the condenser, it will be remarked that car# bon is in some respects a 'preferred material for forming the condenser rods or plates, but if rods or plates of this material were in contact with the ZnO of the charge they would soon be damaged, 'and unless electrically insulated from the resistor they would 2o be likely to shunt current from the latter. This objectionable featurecan be avoided by utilizing short pieces of rods or plates formed of say carborundum, which are preferably place`d next to both the resistor and charge, as indicated by 2S, Fig. 1.

T o realize high effective thermal efficiency in the resistor it is important that the temperature in the sump W shall be as high as possible, or in the reverse way of exv pressing it, that the difference of temperature as between the lower surface-of the resistor and the upper surface of the sump sole z' shall be as little as possible, wherebyl there willbe little tendency for the' flow of 85 the heat units .to the sump and whereby there will be a maximum tendency for .the heat units to flow upwardly and to the sides of the 'reaction chamber. Moreover, .a high -temperature is preferable for the residue, as 40 it serves to prevent vthe latter from caking when primarily of a sintery characteristic, or to keep the residue'in a iuid'state when it possesses a primarily fluid characteristic.

In order to resist chemical attack the sole $5 7 is preferably constructed in the main part ofv such material as tamped carborundum sand or a mixture of crucible graphite and clay. These materials, however, are good conductors of heat and the problem which then 'arises is'to provide eective heat insulation. l There are several waysin which A this may be accomplished. One manner'of `satisfactorily realizing eifective prevention of thermal energy from the sump is here indicated. For example, the outer ortion, as

' 29, of the tamping material use for making the sole is mixed witha large proportion' of broken or granular kieselguhr, that is infusorial earth previously made up with a binder and highly heated, ,thus roducin al very porous structure; next to t is are t in l ie,sclf. ;11hr` bricks, as 30,' and, surrounding all is a box of cellular asbestos board 31. The thickness of such an insulating belt or f sheathing vneed not usually vexceed from rundum walls in which cores are placed, the 'withdrawal of whiclrwould leave slits, or

.ing located in the walls of the furnace and about four to six inches, whence the compression due to the overhead weight will be of negligible amount.

Attention is directed to the fact that all of t-he spaces, galleries or chambers can be o easily reached for inspection, cleaning or repair, which is an advantage of importance in the operation of a commercial plant.

It will be apparent to those skilled in the art that'various modifications can be made 5 in the design without, however, departing from its spirit and essence. In justification of this averment it will suifice to point out as follows: Thus in the reaction chamber side walls, instead ofusing small separable members, relatively large slabs, blocks or a solid tamped structure may be substituted in which perforations, slits or ducts can be numerously molded. In fact, the plan has been considered of forming tamped carbooilsoaked strips or pencils of wood, or saw dust, or paper tubes can be laid, the ultimate burning out of which, like straws in bricks, would produce a highly porous structure. Indications of the foregoing are denoted in the diagram, Fig. 4, in which horizontal staggered' slots 32 and vertical slits 33 are shown. Again in the same figure a stack QFvery thin plates is indicatedyl, cemented together with interposed granular particles as 35, which would produce a structure containing a great number of slits having capillarial and diiusive characteristics of a high order.

What I claim is y 1. An electric furnace having a horizontal carbon resistor, two sets of terminals each' vcomprising a plurality-of carbon terminal members the ,inner ends of Asaid terminal members bem in contact with the resistor and located within the walls of the furnace, the outer ends of said terminal members be` two mts. of metallic strips which protrude from vthe walls to the exterior of the furnace,

one set of'said metallic strips connecting the 'l outer ends of carbon members constituting one set of terminals and the other `set of said metallic strips connecting the outer ends of carbon members in the other set of said terminals.

2. In an electric zinc furnace having perforatedreaction chamber walls contiguous and Vconnected to vertical extraneous spaces or galleries,- the combination therewith of van underlying receptacle for receiving prod-l ucts of the reaction.

8. An electric zinc 'furnace having' Vreac- 125 tion chamber. side 'walls provided with a plurality of outwardly extending side openaving -vertical ingsl a. connectin .portion spaco or spaces tr'ough which products of the reaction pasado'whwardl'y after having 1345 BEST AVAlLABLE COP.

passed the chamber side wall openings, and

anotherl space or spaces through which por- A 5. A condenser of the classy described: com-` prising the reaction Achamber walls of a furnace and outerwalls and having interposed between said walls vertical up-low and down-flow spaces or galleries.

6. A condensing apparatus having vertical down and up-low spaces or galleries located between 4walls each of which .are provided -with perforations that slope in' wardly and downwardly. Y 7. In an electric zinc furnace, lthe combination with a resistor supported upon an open grating, of a residue sump, a tamped sole and a sheathing therefor, highly impervious to heat conduction.

8. An electric zinc Afurnace having perforated'walls' atthe sides of the reaction chamber through which products of the reaction can pass,` each of said wallsbeing provided with a blanketing chamber which receives the residual gaseousproducts of the reaction andfrom which chambers said gaseous products can pass to the atmosphere.

9. An electric furnace having terminals at opposite ends, an electrical resistor between the terminals and a blanketing chamber in the side walls thereof. 1.0. A combined electric furnace of the resistor type and a fume condenser having lin the walls a blanketing chamber between which and the reaction zone in the furnace the condenser islocated.

1'1. An electric furnace having a resistor,. a condenser arranged to receive the prcducts of reaction through the side walls of the resistor-containing chamber and a blanketing chamber arranged to receive the residual gaseous products of the reaction after metallic fumes haveV been condensed vto liquid metal.

. 12. In a combined furnace for producing metallicfumes and a condenser for receiving and-{condensing said fumes, the combination vof a resistor, openings in the side walls of the reaction chamber through which` o enings the products of the reaction pass directly .to the condpnservfrom which residual gaseous pro ucts Vcan passte-ablanketing' chamber andthene' to the 'atmosphere, the blanketing chamber being ar,- ranged in the side wall of the furnace and -the condenser above referred to being i0-- cated between theblanketing chamber and the reacting chamber., This 'specification-signed and witnessed this 31p day of December A. D. 1912.

Copies otthil patent may'be obtained for ve' cents veach, .by addressing the Commissioner of Patenti, Washington, CD. C. 

